1. Field
The present disclosure relates generally to antennas, and in particular, to wideband beam-forming antennas that are electronically scanned.
2. Background
Antenna systems are used to send or receive radio frequency (RF) signals. These radio frequency signals often include information such as voice communications, images, messages, and other types of information.
One type of antenna system commonly used is a directional or beam-forming antenna. This type of antenna radiates or receives greater power in specific directions allowing for increased system performance and reduced interference to unintended receivers or from unintended transmitters. Wideband antennas are often used when substantial frequency range or multiple functions are desired. For example, aircraft wideband antennas may have multiple functions such as sensors, communications, and electronic warfare. Further, the beams from these antennas are often steered. The steering of the beams may be performed electronically or mechanically.
With respect to the use of these types of antennas on aircraft, weight and size are often a factor, in addition to performance. For example, motorized gimbals have been used to mechanically steer beams from antennas. Motorized gimbals, however, increase the weight and require additional space in the aircraft, and limit the beam-steering rate to lower than necessary for some applications.
Electronically steered antennas may be used to reduce weight and improve beam agility. However, typical radiators used in these types of antennas also result in more weight than desired for some applications. For example, existing electronically steered antennas often employ heavy and bulky slotted waveguides formed from rectangular copper pipes as used with some current architectures below Ku-band. This type of solution may be lighter than the use of a gimbal for azimuth, elevation scan, or both, but still may not meet desired weight requirements for some applications on aircraft or other types of vehicles, such as a spacecraft.
Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues. For example, it would be desirable to have a method and apparatus that overcome a technical problem with steering beams over wide frequency range and field-of-regard from an antenna using an architecture that has a desired weight and performance.